It is known that hindered polyalicyclic alkyl catalyst precursors are useful in catalyst compositions for the production of polyethylene, especially high density polyethylenes useful in such products as films and blow molding products. The synthesis of such supported hindered polyalicyclic alkyl catalyst compositions is described in U.S. Pat. Nos. 3,704,287 and 3,642,749. However, their use in a gas-phase process, where problems caused by the presence of reactor fines (small average particle size polymer particles) must be overcome to be commercially viable.
Furthermore, the synthesis of hindered polyalicyclic alkyl catalysts must be improved. The synthesis of such catalyst compositions as described in U.S. Pat. Nos. 3,704,287 and 3,642,749 includes the use of diluents such as aromatic and/or halogenated hydrocarbons, both of which are undesirable diluents. The syntheses and use in polymerization processes of other chromate esters are also described in U.S. Pat. No. 4,065,612, U.S. Pat. No. 5,698,723 and EP 0 454 434 A2. Even in the U.S. Pat. No. 5,698,723, the use of hexane as a diluent is included in the synthesis of the catalyst. These synthesis mostly derive from W. M. B. Könst and J. Th. M. F. Maessen, in 10(12) SYNTHETIC COMMUNICATIONS 905-909 (1980). Another synthesis method of chromate esters, including polyalicyclic chromate esters, can be found in J.-C. Richer and J.-M. Hachey, 53 CAN. J. CHEM. 3087-3093 (1975). The findings of Richer and Hachey suggest that the use of aqueous diluents is not desirable in forming chromate esters. Thus, a practical and useful synthesis of hindered polyalicyclic alkyl catalyst precursors is still lacking in the art. What is further lacking is a useful synthesis method of supported catalyst compositions suitable for gas-phase polymerizations that include such hindered polyalicyclic alkyl catalyst precursors.